A Couple of Questions about files under etc which owned by no package

[郑文辉(Techlive Zheng) <techlivezheng@xxxxxxxxx>]

I ran the script below to see the files which owned by no package.

    export LC_ALL=C
    for dir in bin etc lib usr var sbin;do
            find /$dir -type f -exec pacman -Qo {} \; 2>$dir 1>/dev/null
    done

I got the following.

    error: No package owns /etc/crontab
    error: No package owns /etc/localtime
    error: No package owns /etc/ssl/certs/ca-certificates.crt

Are these files necessary now, could I delete them?